Anadenanthera colubrina (Vell) Brenan: Ethnobotanical, phytochemical, pharmacological and toxicological aspects

Anadenanthera colubrina (Vell.) Brenan is an endemic tree to South America and different parts of it are used by the population for the treatment of various diseases, as well as in indigenous rituals. This species has high pharmacological potential but may present toxic potential due to the presence of psychotropic compounds. To review published studies with the species A. colubrina regarding ethnobotanical, phytochemical, pharmacological and toxicological aspects, as well as discuss perspectives for new research and protection of this species. A literature review was performed by accessing published articles on databases such as: PubMed, Science Direct, Scielo, Scopus, Taylor and Francis online, Springer Link, National Center for Biotechnology Information (NCBI), ACS Publications, Chemspider and Google Scholar. The keywords used were: “Anadenanthera colubrina” or “Mimosa colubrina” or “Piptadenia colubrina” or “Piptadenia macrocarpa” or “Piptadenia grata” or “Anadenanthera macrocarpa” and “medicinal plants” or “pharmacological” or “phytochemicals” or “traditional use” or “toxicological” or “ethnobotanical” or “pre-clinical trial” or “clinical”. Articles found by database searches and search engines were screened at four stages: (i) title screening, (ii) locality screening, (iii) abstract screening, and (iv) full text. Other articles found through supplementary searches were screened in the full text whenever available. Each article was assessed by three reviewers at the title and abstract screening stages, except for those found in Portuguese databases that were assessed by the native reviewer. This robust tree has been popularly useful for agroeconomic, medicinal and as a hallucinogen in religious rituals. According to the published studies, the main parts of the plant are the bark and seeds that are mostly used for respiratory conditions and as entheogens, respectively. It is a rich traditional herbal medicine with many pharmacological properties such as anti-inflammatory, antinociceptive, antidiarrheal, wound healing, antimicrobial, antitumoral, antioxidant, antiaddictive, insecticide and allelopathic that were described in in vitro and in vivo assays, and approximately 56 compounds were identified, suggesting a therapeutic potential for this species. Although most relate to medicinal uses, these are preliminaries and do not show the mechanism of action. The phytochemical assays showed the presence of phenolic compounds, flavonoids, triterpenes, steroids and alkaloids. Some of the compounds are anadanthoflavone, which is exclusive to this species, and no pharmacological or toxicological studies have yet demonstrated this compound. Another important compound is bufotenine which was isolated from seeds and is related to hallucinogenic and antiviral activity. The extracts made from leaves, bark, gum, and fruits appear to be safe, according to both in vivo and in vitro toxicology testing, which all shown low toxicity. Due to the presence of bufotenine in the seeds, it can be toxic, however, it was not found in toxicological assays with the seed extracts. Therefore, part of the studies confirms the popular use of A. colubrina, however, more assays with isolated compounds and with the different extracts are necessary to corroborate other uses and the mechanism of action of their pharmacological effects needs to discuss in more detail. Therefore, the present review would be identified the gaps and suggests further studies oriented to validate the popular use. Thus, it must be noted that the use of this species must be controlled in order to minimize the environmental impact, as most of the pharmacological potential was shown with the bark and seeds. Due to its wide use in folk medicine, it is part of the Brazilian medicinal species with priority for conservation.